Flight lieutenant is a rank in the British Royal Air Force and many other air forces around the world. This rank is equivalent to a captain in the British Army and the Royal Marines. Some synonyms for flight lieutenant include air force lieutenant, airman first class, aviator, and squadron leader. In the United States Air Force, the equivalent rank is a first lieutenant. This rank is also similar to that of a lieutenant in the navy or coast guard. Regardless of the specific title, all of these ranks are leadership positions in their respective branches of the military and require extensive training and dedication.